Central Vacuum and Hide-A-Hose in a Passive House

My wife was very against central vacuum in the house, and for a long time, we determined not to install a central vacuum system.  (She despised having to carry around the long hose - and she'd had only a little experience of this before, but it was with a very long and heavy old style of hose.  Today's hoses are much lighter and more flexible.)  In addition, we didn't know if central vacuums and airtight houses would work well together - but this ended up being just a small part of the project.  The answer is just to place the central vac inside the house, and do not vent it. - But even venting it might be fine (we've not tried this as yet).

Given the very long time it was taking to build our house, I was able to research this more and more, and I eventually realized that cleaning and maintaining the building was of great importance - and this ongoing job would be done better and more frequently if the cleaning process was made easier and more pleasant - so investments in the building maintenance systems seems a good idea.  Moreover, the lovability of a building is likely to have a lot to do with the ease of keeping it tidy.  A major criticism of larger houses is the effort required to keep them clean, right after the energy required to keep them conditioned.

In the end, I decided to purchase a cheap, used central Vac (it was a decent unit, actually) and install it and see how it worked. The nice thing about getting a cheap used one is that we could clean up the construction mess - even drywall dust, and not worry too much about destroying an expensive unit.

The best central vacuum strategy appears at this time to be the Hide-A-Hose approach, in which the flexible hose is 'garaged' in the rigid tubing inside the walls and frame.  If you are not familiar with this, I encourage you to youtube it.  The needed length of hose is pulled right out of the outlet for vacuuming.  When finished, the hose is sucked back into the outlet by the vacuum force.  This means no coiling of the hose, so very little entanglement, and no carrying hoses around.  I find the costs for this system are overly high (we had a consult with a dealer), so we went about doing what we could to do it ourselves.  The dealer discouraged us over and over again from installing it ourselves, but we did it anyways, and it turned out perfectly fine - really there is no big mystery to it, but I will outlay some of the design points below:

1. First, the tubing that forms the garage must be dedicated without any tees.  This means the run must be planned long enough to avoid any section with a Tee.  We basically ran the tubing in circles around the room to get the required dedicated length.  We wanted more than one outlet per floor due to the way our space would be used, so our layout consisted of a central pipe with branches leading to each hose 'garage', which would wrap around the room and come back to the centre of the house where the outlet would be.
2. The tubing is standard central vac tubing, but the elbows must be the the special extra-long radius Hide-a-Hose elbows - they come in 90, 45, and 22.5 deg.  You can buy them online easily enough.
3. The outlets need to be placed 4' above the floor if the pipe comes from above, and lower if from below - we placed ours at 4' above the floor as all our outlets came from above (so this allows the ergonomic pulling down of the inside hose).
4. If possible, place the garage tubing in the same horizontal plane - this prevents the hose from falling out of the garage when it is mostly out - but no big deal.  Our first install was with 3.25 elbows, and mostly not in plane - still works fine.
5. USe 'Rapidflex' tubing as the hose - available online.
6. The dedicated run for the hose garage needs to be about 5' longer because the rapidflex hose stretches a fair bit sometimes and can get a little stuck in upstream fittings if there is no extra length in the garage section.
7. Plan your runs very carefully.  Try to get a central location in the house to minimize HAH outlets per floor, and keep in mind the HAH elbows - should be max 3  x 90's per garage, less is better - but our first one is 3.25 (3 x 90 and a 22.5) - and it works fine.
8. Silicone spray applied to the rapidflex hose helps a lot to make the hose come out smoothly.  We've not used any and it still works fine.
9. When gluing pipe and fittings, apply the glue only the male part of the joint, to avoid getting any glue inside the pipe.
10. In my first use of the HAH vacuum, I sucked up a short wire with a little plug on it - it got stuck.  I was able to remove it by disconnecting part of the pipe in the basement and using a shopvac to blow air into the pipe in the reverse direction from which the dust usually flows, and this cleared the jam.  I wish there were clean-out fitting for central vac, but I've not seen any.
11. The dealer told us again and again that special, powerful vacuums with true cyclonic action were required to make the HAH work.  Well these are only available through them at high prices (about $1000).  I tried my cheap 2nd-hand ACV vac ($150) with the HAH and it works perfectly fine so far.
12. I complain the prices are high for HAH, and they are.  However, if installation comes with those prices, you might get a good value - but I wanted to install it myself, so the component prices seemed ridiculous to me.  Each outlet (just the outlet) is $230 (includes rough-in kit) - compared to about $10 for a regular central vac outlet.  But I couldn't find any alternative to this.  The elbows are about $15 each online.  ($45 each at our dealer).  The rapidflex hose was about $90 for 30'.
13. Central vacs appear to be a slow-moving technology (probably due to the sometimes dumb patent protections).  They should have adopted brushless motors a long time ago - but Ametek Lamb only offer one or two units out of their huge selection with brushless motors.  Also I do agree with the true cyclonic action, but not for twice the money.  The self-cleaning filter units seem OK.  Having central vac to clean construction messes seems great so far.  I'd like to install one in the garage as well.
14. There is a product called Zoom - appears to be a very good value for money compared to the HAH.
15. Power:  I'm always amazed at how manufacturers market the 'power' of their appliances.  I think most consumers know that the amount of power a unit consumes has little to do with the amount of useful work the unit produces.  In the case of central vacuums, airwatts is a fairly good measure of performance, which describes the useful 'power' of the actual vacuum, not the electrical power going into the machine.  However, there is a measure which is better yet:  This is inches of water column (pressure or vacuum) at a given flow rate.  The better machines seem to offer about 125 inches water column at some 150 cfm.  These two numbers together give you a very clear idea of the suction pressure and the flow rate.  Dust collectors have quite different pressures and flow rates - but they can have the same 'airwatts', which is the product of suction and flow. 

Having installed the central vac now, we have both HAH and regular outlets, I can say that it seems much better to have central vac than not, and the HAH is definitely worth having, especially if can do it for less money than what we were told it would be.  The suctionof a central vac is a lot stronger, and the convenience a lot better, and you never have to go looking for the vacuum, nor do you ever have to drag it around.  It can also be more quiet, since the machine is generally not close to where you are working.

Central Vac Pipe with extra long radius bends for Hide a Hose

Hide a Hose Outlet, with Rapidflex hose

Hide a Hose outlet, rear

Hide a Hose Outlet, front side with door open